As a rule tracks for rail vehicles are laid on beds, grit or compacted and optionally reinforced soil, on embankments of compacted material or on concrete plates, which lie directly on the ground (DE-OS 29 01 283, DE-OS 23 54 958). Such tracks are also frequently laid on gravel. The soil and a gravel bed or the like, are elastic within certain limits, thereby forming a spring cushion which provides a minor damping of the impact noise.
When in tracks laid out in the above manner elastically supported rails are used for further reduction of the vibrations resulting from the vehicle movements on the tracks and the related impact noise, the characteristic frequency of the elastic rail support acting as a spring interferes with the characteristic frequency of the second spring formed by the soil or gravel bed, such that the intended reduction of the impact noise is not achieved, or that shifts occur in the frequency ranges with possible increase in the noise.
Further an infrastructure is known wherein under each rail of the track a longitudinal sleeper is provided, consisting of a continuous rigid girder (DE-OS 40 27 836). Due to this construction of the infrastructure, the latter has such a high bending moment that no bending or only a negligible bending of the infrastructure can take place and the spring effect of the support layer is cancelled out.
In order to avoid the aforedescribed disadvantages, a further known infrastructure is designed so that each rail of the track with the pertaining frame halves is embedded in a trough, whereby one frame half rests directly against the one lateral trough wall, and the other frame half rests against the other trough wall via a wedge (DE 44 27 237 A1). This infrastructure has proven to be very advantageous. However it can not be used everywhere.